1. Field Of The Invention
This invention concerns an improved process for the preparation of strong, dyeable, heat resistant filaments of synthetic polycarbonamides from polycarbonamide-forming compositions containing a soluble copper salt, a metal halide and a phosphorus compound.
2. Description of the Prior Art
Shaped articles such as fibers, yarn, filaments, staple, pellicles, molded forms and the like produced from a polyamide are well know. Such materials are commercially known as nylon. Preparation of polymers suitable for use in manufacturing such shaped articles may be prepared according to the processes described in U.S. Pat. Nos. 2,071,250; 2,071,253; and 2,130,948. In order to attain various improvements for certain specific applications, numerous modifications of the basic processes have been suggested. For example, Stamatoff U.S. Pat. No. 2,705,227 teaches that resistance to oxidative degradation can be enhanced by inclusion of a combination of: (1) a dissolved copper compound, (2) a halogen compound, and (3) a phosphorous acid compound. Anton U.S. Pat. No. 3,377,314 teaches the use of hexamethylene diammonium phenylphosphinate in combination with cupric acetate and potassium iodide for polyamide yarns having for instance high strength, whiteness, high dye-absorbability, resistance to thermal degradation and good processability.
Molten polyamide compositions of Anton have a tendency to lose copper during processing by the formation of polymer-insoluble copper compounds or metallic copper. Particles of these deposits in time cause problems for continuous, commercial, polymerization and spinning processes, particularly at higher phosphinate concentrations in the polymer. The resulting lower copper content also provides less protection in the filaments.